Key to the Species. 
White bases to tail-feathers 
Black bases to tail-feathers 
No white bar on wing 
White bar on wing 
Under tail-feathers white 
Under tail-feathers black 
also 
Black under tail-coverts . . 
White under tail-coverts 
No white bar on wing 
White bar on wing 
Bases to tail-feathers white 
Bases to tail-feathers black 
. . S. graculina. 
. . S. melanoptera. 
. . S. versicolor. 
. . S. fuliginosa. 
. . S. fuliginosa. 
. . S. melanoptera. 
. . S. graculina. 
S. versicolor. 
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